Steam-superheater.



N0- 798,'705. PATENTED SEPT. 5, 1905.

D. ROBERTS. STEAM SUPERHEATBR.

APPLICATION FILED SEPT.6. 1904.

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PATENTED SEPT. 5, 1905.

D. ROBERTS.

STEAM SUPERHEATER.

APPLICATION FILED SEPT.6. 1904.

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STEAlVl-SUPERH EATER.

Specification of Letters Patent.

Patented Sept. 5, 1905.

Application filed September 6,1904. Serial No, 223,417.

Be it known that 1, DAVID ltonnu'rs, a subject of the King of (ireatBritain, residing at Spittlegate Iron \Vorks, (:i-rantham, county ofLincoln, England, have invented new and useful Improvements inSteam-Superheaters, of which the following is a specification.

This invention relates to improvements in steam-superheaters, and hasfor its object to provide a superheater in which the expansion of thevolume of the steam will distribute and regulate the flow of the steamand wherein, while the maximum economy of heat is obtained, the tubescontaining the steam and transmitting the last stage of superheat arenot subject to the action of the hottest gases.

in many existing super-heaters the current of steam to be superheated iscaused to flow, for the purpose of economizing heat, in a directioncontrary to that of the flow of the hot gases, thereby subjecting partsof the tubes both internally and externally to the greatest heat andrendering them liable to corrode.

Now according to my invention the tubes in which the steam issuperheated are so made say curved or of a U shape--that both their endsare brought to the same side of the su1)erheater-chamber, where they arefixed in suitable boxes to form a nest of tubes. Several nests of tubesmay be superposed and suitably connected at the box ends to form thecomplete super-heater. The steam is admitted to the bottom nest of tubesand being gradually heated and expanding in volume as it passes upwardlywill flow and distribute itself through the tubes proportionately to theheat transmitted to it from the hot gases.

In the accompanying drawings, Figure 1 is a sectional elevation of asteam-superheater constructed according to the invention, the sectionbeing taken on the line 1 1, Fig. 2. Fig. 2 is a sectional plan viewthereof, the section being taken on the line 2 .2, Fig. 1. Fig. 3 is asectional end elevation of the superheater, the section being takenalong the line 3 3, Fig. 2; and Fig. 1 is a front end elevation of thesuper-heater, the left-hand *asing and doors being removed.

1/ represents the chamber of the superheatcr, and (y (I w show nests ofsuperheater-tubes, which are, as above desbribed, of a U shape, bothends of each of the tubes being brought to the same side of thesuperheater-chamber and being fixed in the boxes f I/ /z i,respectively. The tubes are connected together, so

as to form a continuous zigzag passage for the steam, by means of theconnectmg-pipes j. which are secured to the boxes f I 1'.

as clearly shown in Fig. l. The steam to be superheated enters thethrough the inlet-pipes Z', and the superheated steam passes out fromthe topmost box 1' through the outlet-pipes The superheaterchamber 1/ isdivided by a horizontal partition 1 into an upper crmipartment u and alower compartment 0. the latter containing the lowermost nest ofsuperheater-tubes and the former the remaining nests.

is the furnace for supplying the heat, the said furnace being locatedbeneath the superheater, with the lire-d ors 1 1 at the same side as theinlet and outlet for the steam. The gases of combustion from the furnace)1 are conveyed through the flue w around the compartment 0 into theupper compartment //of the super-heater, as iin'licated by the arrows,Fig. 1. The gases then flow upwardlythrough this compartment, bathingthe super-heatertubes therein and communicating heat to the steamflowing through the same and escaping through the fine A, which opens atits lower end into the lower compartment n, through which the said gasesflow and escape through the outlet-flue zto the chimney. lt will thus beseen that the gases [irst impart heat to steam which has been partiallysuperheated, then to steam receiving its linal increment of superheat,and finally to the steam just entering the super-heater.

A by-pass tlue u, having a damper r, is provid ed for enabling the hotgases when desired to be passed directly to the chimney without flowingthrough the superheater.

w is a battle in the upper compartment 11 of the superheater fordistributing the flow of gases among the tubes, and any number of suchbattles may be provided for obtaining the requisite distribution.

11' .r are doors for permitting access to be had to thesuperheater-tubes for purposes of cleaning and renewal, and 1/ 1/ aredoors for enabling acccss to be obtained to the boxes f (7 it 1' and tothe superheater-tubes.

1n the drawings l have represented only one nest of tubes munely, thenest b as being located in the lower compartment 11, but two or morenests may be arranged therein, the number being varied to suit thequantity of steam to be superheated and the temperatureof superheatrequired. l ui-thermore, the air supplied to the furnace may be heatedbelowermost box f fore its entry into the same, it being caused to passthrough passages z 2, ,Fig. 2-, in the superheater-casing. Thesepassages communicate with the under side of the fire-grate, and the flowof the air is regulated through the medium of the door .2.

The separate nests of tubes, instead of-be ing fixed in boxes, may befixed in a flat header and the flow of the steam regulated by internalbaffle-plates.

It is to be noted that in my improved construction the steam enters atthe lowest point of the superheater and continually moves horizontallyor ascends as it passes from one set of tubes to another, so that thesteam is never made to descend at any stage of its passage through thesuperheater. It will also be seen that when a greater degree of heat istransmitted to the steam contained in any tube on the same level withsteam in other tubes which is receiving the average increment of heatthe steam which receives the extra heat will begin to flow upward at agreater velocity, by virtue of the fact of its greater expansion andlower specific gravity. Conversely, steam receiving less than theaverage degree of heat will be retarded in its fiow, the steam thusdistributing itself proportionately through the pipes in accordance withthe amount of heat transmitted to it.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is 1. In asteam-superheater, the combination with afurnace, of a series of superposed nests of horizontally disposed Ushaped tubes, boxes connected to the ends of said tubes,connecting-pipes for said'boxes, a steam-inlet connected to thelowermost box, whereby the flow of the steam through the superheater iscontinually in horizontal and upward directions, substantially asdescribed.

2. A steam-superheater comprising a furnace, a series of superposednests of horizontally-disposed U-shaped tubes connected together, asteam-inlet connected with the lowermost nest of tubes and asteam-outlet connected with the uppermost nest of tubes, whereby theflow of the steam through said ward directions and means for directingthe furnace-gases first into contact with intermediate nest of tubescontaining steam which has already received an increment of heat, theninto contact with the nests of tubes adjacent to the steam-outlet andthen into contact with the tubes adjacent to the steam-inlet,substantially as described.

3. A steam-superheater comprising a furnace, a series of superposednests of horizontally-disposed U-shaped tubes, boxesconnected to theends of said tubes, connecting-pipes for said boxes, a steam-inletconnected to the lowermost nest of tubes, a steam-outlet connected tothe uppermost nest of tubes, ahorizontal partition dividing the furnaceinto compartments, said partition being arranged between certain of saidnests of tubes, a flue for conducting the. gases from the furnace to thelower part of the upper compartment first, a flue connecting saidcompartments and a passage for conveying the gases from the lowercompartment whereby heat is first applied to the steam which hasreceived an increment of heat, then to the steam receiving its finalincrement of superheat and lastly to the steam as it enters thesuperheater, substantially as described.

4:. In a steam-superheater the combination of a furnace, of a series ofsuperposed nests of tubes of a curved or U shape, of boxes to which bothends of the tubes are connected, of connecting-pipes for the boxes, of asteaminlet to the lowermost box, of a steam-outlet from the uppermostboxes and fines and baffles for causing the hot gases from the furnaceto first flow around the upper nests of tubes in a direction from belowupward and then the lowermost nest or nests of tubes, substantially ashereinbefore described.

DAVID ROBERTS.

Witnesses:

HENRY CHARLES ANsLEY, A. ALBUTT.

5o tubes will be continually in horizontal and up-

